1. Field of the Invention
The present invention relates to a laser cutting system in which a laser beam is directed or steered through a predetermined cutting path along a substrate or workpiece to cut the substrate or workpiece. In particular, the present invention relates to a steering mirror assembly for directing the laser beam.
2. Description of the Related Art
Blister card packaging is used to package and display small items at a retail sale location. One example of blister card packaging is the packaging used for small batteries, which generally includes a blister card including various display and informational graphics, to which a plastic bubble piece or “blister” is attached for containing the batteries.
Typically, the foregoing types of packaging blister cards, display cards, clamshell inserts, etc., are printed on a large sheet of cardboard stock, and several different types of blister cards may optionally be printed on one sheet of cardboard stock to save material. A die-cutting process is used to cut the individual cards from the sheet of cardboard stock, requiring a custom-made die which is used with a press to cut the cards from the sheet of cardboard stock. Thereafter, the blister cards are removed from the sheet, stacked, and packaged for shipment to the product manufacturer.
A problem with this arrangement is that for each particular layout of blister cards on the blister card stock, i.e., for each customer order or production run, a custom-built die is needed. This requires the blister card producer to build and stock a large number of custom-made dies.
In view of the foregoing concerns, as well as similar concerns in other industrial applications, high power laser cutting systems have been developed for cutting articles from a substrate material or workpiece. In one approach, the substrate material itself is moved in two dimensions while the laser beam is held stationary. In another approach, the substrate material is held stationary while the laser-generating device is itself moved in two dimensions with respect to the substrate. In a still further approach, the substrate is held stationary, and a steering mirror assembly, including two or more separate, individually-controlled movable mirrors, is used to reflect and direct the laser beam along a cutting path. Typically, two mirrors are used, one controlling an X-axis component of direction of the laser beam and the other controlling a Y-axis component of direction of the laser beam. The individual mirrors are actuated by mechanical systems, such as motors, which are either directly connected to the mirrors or coupled to the mirrors through a gear drive, a screw drive, or other mechanical drive means.
Disadvantageously, because mechanical drive systems for mirrors used in laser steering systems incorporate mechanical drive components such as gears and belts, for example, friction is generated during operation, which limits the speeds at which the mirrors may be moved, and in turn limits the operational speeds at which the laser beam can process a substrate material or workpiece. Further, mechanical drive systems may be prone to failure due to mechanical fatigue or breakage, and typically require skilled maintenance to ensure that the drive systems operate properly.
What is needed is a laser cutting system for cutting articles from a substrate or workpiece which is an improvement over the foregoing.